How are heart rate and blood pressure impacted as you change your fitness?
First, what is Heart Rate (HR)? Generally speaking heart rate is the amount of times your heart beats in one minute (bpm). But really resting heart rate (RHR) is the heart rate measure that matters the most when it comes to track changes in your hearts fitness and efficiency over time. RHR is the number of beats per minute (bpm) your heart makes when you are at complete rest. This measure is best taken when you first wake up in the morning and have not sat up. But you can also take it after sitting quietly or laying down for an extended period of time (ideally at least 10 minutes).
How can you measure your RHR? You can check your resting heart rate simply by counting the number of beats you feel in an artery(e.g. In your neck or wrist) in 15 seconds and multiplying that by 4. Do this first thing after you wake up and are still lying quietly in bed. Write it down and track it for a week so you can get a good average of your RHR. There are also free apps that will measure your heart rate using the flashlight on your phone and your finger. Many smart devices like Fitbits and Apple watches also come with a built-in heart rate monitor that will check your heart rate over time. This is an easy way to let you know how your resting heart rate is changing over the week, month, year.
What is a normal range? A healthy adult resting heart rate can vary widely, but generally between 60-100bpm is considered to be a normal range. It is important to note that some medications and health conditions will impact how much you can alter your own resting heart rate, so talk to your doctor or pharmacist about your medical conditions and medications to have a better understanding of your unique situation.
Why does it matter? Generally, your resting heart rate is a good indicator of heart function and cardiovascular fitness. A normal average resting heart rate (RHR) for an Adult is between 60-100 bpm and a well trained athlete or regular exerciser might be around 40-60 bpm.
Why does your resting heart rate get lower in response to routine exercise? As you increase your physical activity, your body will note the increased need for oxygen by your muscles. In response to this increased need for oxygen because of the increased activity, your body will start increasing its production of red blood cells. With more red blood cells circulating in your body your blood will be able to carry more oxygen around to supply the active muscles. This means that over time, your resting heart rate will gradually lower as your circulatory system gets fitter and more efficient. Basically if you have more red blood cells and therefore, are more able to meet your increased oxygen needs, then with each heartbeat your heart is capable of delivering more oxygen throughout your body. That means that when you are resting, your heart rate can slow down because each beat is delivering more oxygen to your body compared to your less active lifestyle.
What about blood pressure?
Now that we know more about how heart rate is impacted by our fitness, lets talk about blood pressure. As we explore Blood Pressure (BP), we will learn why we should care about the pressure numbers and how we can change those numbers with a little effort. Blood pressure is a measure of how hard your heart has to work to push the blood around your whole body. When your health care professional measures it, or you use a home monitoring system, you get a systolic and a diastolic pressure reading. The results are provided in millimeters of mercury (mmHg). Systolic is the top or larger number that we say in blood pressure and it is the pressure in your arteries when your heart is squeezing the blood out to your whole circulatory system. While the bottom number or the smaller number is your diastolic measure which is the pressure in your arteries when your heart is relaxing and filling back up with blood preparing for the next squeeze (contraction).
What is a normal BP range? A blood pressure reading between 90 to 120 / 60 to 80mmHg is considered to be within a healthy normal range. A blood pressure higher than the normal healthy range is considered hypertensive, and can put an individual at risk of a cardiovascular event like heart attack or stroke. Having a blood pressure below the healthy range is considered hypotensive, which can increase the risk of feeling lightheaded, nauseated, or in some cases fainting, especially with sudden postural change. As we learned last month, with resting heart rate, medications and health conditions can impact blood pressure, as well.
When is the best time to measure your BP? First thing in the morning, take the three measures over 20 mins and average the numbers. For Example, 122/76, 118/80 & 120/78 = 120/78mmHg. Note this down every day for a week.
Which number do we care more about, the Systolic or the Diastolic? Blood pressure is determined by the Systolic contraction/squeeze phase of your heart and the Diastolic relaxation phase of the heart.
Why does it change over your lifetime? With age and less than ideal lifestyle choices, your arteries can become stiff and clogged, resulting in significant increase in resistance to the flow of blood through your body. The increased resistance results in the heart having to work or squeeze harder to circulate the blood,, ie. resulting in higher blood pressure. Physical activity can help to increase the flexibility of arteries, resulting in a gradual reduction of blood pressure over time. Remember the heart is a muscle. The stronger a muscle is the better it can contract. There the systolic pressure (the contracting pressure) will vary more with activity compared to diastolic blood pressure. If you take your blood pressure immediately after finishing a workout, you will notice that your systolic reading is significantly higher compared to at rest.
If we bring it back full circle to heart rate, there is a close relationship between the two. The same factors that improve your resting heart rate also impact your blood pressure. We don’t want to dwell upon this but exercise is the centre of establishing and maintaining a healthy body. Exercising the body exercises the heart. This increases the oxygen carrying capacity of your blood, which lowers your heart rate, allowing you to pump more oxygen around with less effort resulting in reduced blood pressure.
How can you test? The easiest way to test your blood pressure is to sit down at one of the blood pressure stations in your local pharmacy. Or you can also purchase an at home blood pressure monitor unit, but they do require calibration in order to be considered accurate.
Things to consider!! If you are someone who is living with either hyper or hypotension, changing your activity and fitness can be more challenging without qualified supervision. There are safe ways to participate in physical activity at both ends of the spectrum, but checking in with your health care professional (Physical Therapist, Doctor, Nurse Practitioner, or Athletic Therapist) before changing your current physical activity is always a good idea if you have any questions or concerns. Let's all keep a healthy heart!